forked from Minki/linux
a2b7861bb3
Currently, in PREEMPT_COUNT=n kernel, kvm_async_pf_task_wait() could call schedule() to reschedule in some cases. This could result in accidentally ending the current RCU read-side critical section early, causing random memory corruption in the guest, or otherwise preempting the currently running task inside between preempt_disable and preempt_enable. The difficulty to handle this well is because we don't know whether an async PF delivered in a preemptible section or RCU read-side critical section for PREEMPT_COUNT=n, since preempt_disable()/enable() and rcu_read_lock/unlock() are both no-ops in that case. To cure this, we treat any async PF interrupting a kernel context as one that cannot be preempted, preventing kvm_async_pf_task_wait() from choosing the schedule() path in that case. To do so, a second parameter for kvm_async_pf_task_wait() is introduced, so that we know whether it's called from a context interrupting the kernel, and the parameter is set properly in all the callsites. Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: stable@vger.kernel.org Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> |
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| .. | ||
| cpuid.c | ||
| cpuid.h | ||
| debugfs.c | ||
| emulate.c | ||
| hyperv.c | ||
| hyperv.h | ||
| i8254.c | ||
| i8254.h | ||
| i8259.c | ||
| ioapic.c | ||
| ioapic.h | ||
| irq_comm.c | ||
| irq.c | ||
| irq.h | ||
| Kconfig | ||
| kvm_cache_regs.h | ||
| lapic.c | ||
| lapic.h | ||
| Makefile | ||
| mmu_audit.c | ||
| mmu.c | ||
| mmu.h | ||
| mmutrace.h | ||
| mtrr.c | ||
| page_track.c | ||
| paging_tmpl.h | ||
| pmu_amd.c | ||
| pmu_intel.c | ||
| pmu.c | ||
| pmu.h | ||
| svm.c | ||
| trace.h | ||
| tss.h | ||
| vmx.c | ||
| x86.c | ||
| x86.h | ||